Simple scoring of whole queries
Not very pretty yet, but usable.

* Can wrap top-level query
* Can use boost and score mode
* Filters for functions have to be added directly
  into the hash
* No boosting of subqueries
Script score can be used w/ options (e.g. filter)
Added boost factor scoring

Fixed doc comments
Adds random scoring
Added field value boosting
Decay function scoring added.
Function score queries with queries
must always be composed
Fixing 1.9 compatibility
Merge branch 'master' into scoring

Conflicts:
	lib/chewy/query.rb
	lib/chewy/query/criteria.rb
	spec/chewy/query/criteria_spec.rb
	spec/chewy/query_spec.rb
Restored lost functions from merge… ;-)
Merge pull request #28 from betterplace/scoring

Use function_score for complete queries